Anatomy and physiology of the male reproductive system
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Anatomy and physiology of the male reproductive system
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Female/male genital homologs p. 641
Male genital embryology p. 639
Transcript
Content Reviewers
The male reproductive system includes internal and external organs and structures that help with reproduction.
The external male sex organs are the penis, and below it, the scrotum.
Inside the scrotum, there are the two testicles, or testes - the male gonads.
Inside the body, there’s a system of ducts through which sperm travel during ejaculation, as well as the male accessory sex glands, which secrete nourishing fluids for the travelling sperm.
Now, the testes are two organs the size of small plums, that are located in a skin and muscle pouch called the scrotum.
This pouch has a line called the scrotal raphe running down the middle, which separates it in two chambers - one for each testis.
The scrotum hangs outside of the body but has several layers of muscles and fascia that keep the testis temperature about 3 degrees lower than body temperature, which is perfect for sperm production.
When it’s cold outside, the scrotal skin wrinkles and the scrotum elevates to bring the testes closer to the body to warm up.
When it’s warm outside, the scrotal skin loosens up and the scrotum lowers the testes away from the body, and heat is released through sweating.
The testes themselves are covered on the outside by the tunica albuginea - a white, fibrous layer.
If we slice a testis open and look inside - sorry for the cringe moment, guys - we can see that the tunica albuginea, sends fibrous projections called septa towards the center of the testis.
These septa partition each testis into about 250 lobules, and each lobule contains at least one and up to four seminiferous tubules, which is where sperm is synthesized.
The seminiferous tubules come together and form a single straight tubule that exits the lobule, and enters a small network of tubules called the rete testis.
Sources
- "Medical Physiology" Elsevier (2016)
- "Physiology" Elsevier (2017)
- "Human Anatomy & Physiology" Pearson (2018)
- "Principles of Anatomy and Physiology" Wiley (2014)
- "Spermatogenesis" Human Reproduction (1998)
- "Intercellular adhesion molecules (ICAMs) and spermatogenesis" Human Reproduction Update (2013)
- "A gene from the human sex-determining region encodes a protein with homology to a conserved DNA-binding motif" Nature (1990)
- "EVIDENCE OF TESTICULAR ACTIVITY IN EARLY INFANCY" The Journal of Clinical Endocrinology & Metabolism (1973)